error: error parsing ssl2.yaml: error converting YAML to JSON: yaml: line 22: did not find expected key

apiVersion: cert-manager.io/v1alpha2
kind: Certificate
metadata:
  name: ambassador-certs
  # cert-manager will put the resulting Secret in the same Kubernetes namespace
  # as the Certificate. Therefore you should put this Certificate in the same namespace as Ambassador.
  # eg. if you deploy ambassador to ambassador namespace, you need to change to namespace: ambassador
  namespace: default
spec:
  # naming the secret name certificate ambassador-certs is important because
  # ambassador just look for this particular name
  secretName: ambassador-certs
  issuerRef:
    name: letsencrypt-prod
    kind: ClusterIssuer
  dnsNames:
  - mikiwiki.es
  acme:
    config:
    - http01:
        ingressClass: nginx
      domains:
     - mikiwiki.es